Crysis 2 isn't particularly hard on super soldier difficulty if you take your time and use cover during fight sequences. If you are having trouble however, I would suggest playing through on easy or normal and upgrade your suit and abilities. Once you beat the game, you have an option of "New Game +" which allows you to play through using the suit and upgrades you already have. I suggest upgrading stealth as much as possible, because in most situations, you can just run through the game unseen.